The definitive Guide to Multivitamins

Multivitamins are an incredibly popular dietary supplement. According to the National Institute of Health, approximately 66% of Americans, including children, adults, and seniors, take multivitamins (1). Many people believe multivitamin supplements provide health benefits, from increased energy levels and immunity, to making up for poor eating habits. There’s a lot to consider before taking multivitamin supplements and steps to take when choosing a multivitamin that’s best for you. This guide provides an in-depth overview of multivitamins, from where to find them to how to decipher between all the different multivitamin products that are on the market.

SEE ALL TOPICS

DON'T HAVE THE TIME TO READ THE WHOLE GUIDE RIGHT NOW?

Ebook cover
Ebook cover

DON'T HAVE THE TIME TO READ THE WHOLE GUIDE RIGHT NOW?

Download the E-Book

Let us send you a copy so you can read it when it’s convenient for you. Just let me know where to send it (takes 5 seconds)

Get the E-Book

What are Multivitamins?

Multivitamins are supplements containing a combination of vitamins and minerals. They’re often referred to as multis, multiples, or vitamins. Each multivitamin is formulated differently, containing different ratios of nutrients. Most multivitamin supplements come in pill form. However, they’re sometimes available in other formats, such as gummies, powders, and liquids. Other ingredients such as herbs, amino acids, and fatty acids are commonly added to multivitamins.

There is no established definition available for multivitamin supplements that defines what ingredients and amounts of nutrients they’re required to contain. Manufacturers decide their multivitamin formulations on their own, including what types of nutrients are added to the supplements and in what amounts.

Types of Multivitamins

Many types of multivitamins are available for use. An overview of the 3 most common types of multivitamins is listed below:

Spoons with supplement pills in them

Once Daily Multivitamins

Basic formulations meant to be taken once a day. Contain most vitamins and minerals required for human health in amounts comparable to the Dietary Reference Intakes (DRIs). Once daily multivitamins are typically available to meet the unique nutritional needs of certain populations at various ages and stages of life.

Pills on a table next to fruit

Megadose Multivitamins

These contain certain nutrients at significantly higher levels than the DRIs. Often include other ingredients, such as herbs. Promoted to increase energy levels, boost immunity, or help with a specific health condition.

Pills on a table next to fruit

Specialized Multivitamins

Often include vitamins and minerals in combination with unique ingredients, such as herbs and probiotics. Aimed to support a specific health goal, improve a symptom, or prevent a disease.

Whether or not you choose a once daily, megadose, or specialized multivitamin will depend on what your specific needs are.

Once daily multivitamins are best for individuals looking for a product to help them fill nutritional gaps they can’t meet through their diet alone, while megadose and specialized multivitamins are generally taken with a more specific health goal in mind.

WHO TAKES MULTIVITAMINS?

Of the one-third of the US population that takes multivitamins, children and older adults are the groups most likely to take them. Research has shown that between 25-40% of individuals in these age groups take multivitamins (2). Women are known to take multivitamins more frequently than men. Additionally, populations with more education and higher income levels have higher reported multivitamin use (2).

Interestingly, the populations at highest risk for suboptimal nutrition intake, such as smokers and certain ethnic groups, are less likely to take multivitamins. On the other hand, people who follow healthy diets and have lower body mass indexes have a higher likelihood of including multivitamins in their regimen (2).

Where to find Multivitamins

Multivitamins are available at most drug stores, grocery stores, and specialty food and nutrition stores. They’re typically found near the pharmacy or health food aisle. There are also several independent supplement companies that sell multivitamins in their own stores, such as GNC. Additionally, most manufacturers have their products available for purchase online. While there are certain multivitamins and supplements that doctors may write prescriptions for, you can purchase most multivitamins over-the-counter.

When to Take Multivitamins

Each multivitamin manufacturer has its own recommendations for when to take its supplements, which will be listed on the label. In general, there’s no “right” time to take multivitamins. Some multivitamins are recommended to be taken on an empty stomach to enhance absorption, while others should be consumed with food to prevent side effects (3). Additionally, some people choose to split their multivitamin dose throughout the day rather than taking it at once. Keep in mind that some nutrients, such as B vitamins, are known to increase energy levels. For this reason, it’s not the best idea to take them at night when you need to go to sleep. You should also consider other supplements and medications you’re taking when deciding when to take your multivitamin. It’s important to consult with your doctor about this, who will provide you with a specific recommendation to prevent unwanted interactions or side effects.

Multivitamin Prices

Multivitamins are of high demand in the US. According to the National Institute of Health, multivitamins account for almost one-sixth of all purchases of dietary supplements. Sales of all dietary supplements in the US totaled an estimated $46.7 billion in 2014, 12% of which was for multivitamins (2). Prices of multivitamins vary depending on the brand, formulation, and where they are purchased. Those that have extra ingredients, such as herbs, added to them tend to be pricier than those with simple vitamin and mineral formulations. Generic multivitamin brands are generally cheaper than name brands. Additionally, those with special seals and certifications such as the CL Approved Quality Product Seal or NSF International Dietary Supplement Certification may be more expensive than those that haven’t been evaluated by a third party.

Regulation of Multivitamins

Multivitamins are regulated by the Food and Drug Administration (FDA) as “dietary supplements.” Federal law doesn’t require dietary supplements to be proven safe to FDA’s satisfaction before they’re marketed. Claims made on multivitamin supplements are also not required to be accurate or truthful before they appear on the product (4). This means multivitamins are subject to much less regulatory supervision than medications. The FDA doesn’t have to approve or inspect multivitamins before they make it to store shelves.

For this reason, multivitamin manufacturers have the capability to list ingredients and make claims on about their products that aren’t necessarily true. This is a major downfall of the supplement industry and demonstrates the importance of researching multivitamins before using them. When serious adverse effects of multivitamin supplements are reported by consumers and/or health care professionals, the FDA follows mandatory monitoring procedures. Discrepancies on multivitamin labels aren’t typically discovered until after they’ve been on the market (4).

Seals on Multivitamins

Many multivitamins have certain “seals of approval” provided by independent organizations that evaluate products for content, strength, and contaminants. While these seals don’t necessarily deem multivitamins as safe or effective, they ensure that products contain the ingredients listed on the label and don’t contain harmful contaminants. Each organization has its own approach to testing multivitamins.

There’s not currently any scientific evidence to show multivitamins that contain these seals to be more effective. However, if quality is one of your priorities when choosing supplements, it’s beneficial to find a multivitamin that contains at least one of these seals.

ConsumerLab.com Approved Quality Product Seal (CL)

Tests supplements based on identity, quantity, purity, and disintegration. Manufacturers using the CL label must have their products tested every 12 months (5).

NSF International Dietary Supplement Certification

Reviews supplement claims, quality, compliance, and safety. Conducts unannounced inspections on products with the certification (6).

NSF Good Manufacturing Practices (GMP)

Establishes guidelines that provide a system of processes, procedures, and documentation to make sure products have the identity, strength, composition, quality and purity that appear on their labels (6).

US Pharmacopeia (USP) Dietary Supplement Verification Program

Indicates the multivitamin contains the ingredients listed on the label, in the declared potency and amount. Also verifies products are absorbable by the human body and don’t contain unsafe levels of contaminants (7).

Common Nutrients in Multivitamins

Although multivitamin brands differ, they generally contain a combination of the 14 vitamins and minerals listed below. They may provide other nutrients depending on the focus of the multivitamin. Here is an overview of nutrients you’ll commonly see on multivitamin labels and their primary functions in the body (8):

Vitamin A

Supports eye, skin, and bone health; boosts the immune system.

Vitamin C

Boosts the immune system; protects against skin aging; promotes iron absorption in the body.

Vitamin D

Supports bone health; helps lower inflammation and supports the immune system.

Vitamin E

Helps maintain a healthy heart; protects cells from inflammation.

Riboflavin

Promotes energy production; supports cellular function, growth, and development; helps metabolize fats, drugs, and steroids in the body.

Thiamin

Helps convert foods into cellular energy; supports growth, development, and function of cells.

Vitamin B6

Helps convert foods into cellular energy; supports protein metabolism.

Niacin

Helps convert foods into cellular energy; supports synthesis of cholesterol and fatty acids; maintains cellular antioxidant function.

Vitamin B12

Required for red blood cell formation and brain health; promotes energy production.

Folic Acid

Plays a role in preventing birth defects; helps metabolize amino acids in the body.

Panthothenic Acid

Necessary for making red blood cells; helps convert foods into cellular energy.

Calcium

Supports bone health and muscle function.

Iron

Helps transport oxygen through the body; supports metabolism and production of red blood cells

Zinc

Helps support the immune system; promotes wound healing

Understanding the Dietary Reference Intakes

Before choosing to take a multivitamin, it’s important to understand Dietary Reference Intakes (DRIs). DRIs are a set of reference values for healthy people used to plan and assess their nutrient intakes. These values, which vary by gender and age, include (9):

Recommended Dietary Allowance (RDA)

Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97-98%) healthy people.

Adequate Intake (AI)

Used when there is not enough evidence to support the development of an RDA. Set at a level assumed to ensure optimal nutritional status.

Tolerable Upper Intake Level (UL)

Maximum daily intake unlikely to cause adverse health effects.

The %Daily Value (DV) listed for nutrients on multivitamin supplement labels is based on the RDAs and AIs. The label provides the %DV so you can see how much a serving of the multivitamin contributes to the DV (2). For example, if a product lists the %DV for Vitamin C as 100%, this means it provides 100% of the RDA for vitamin C.

Nutrients of Public Health Concern

According to the 2015 Dietary Guidelines for Americans, many people consume certain nutrients in amounts below the DRIs (10). Some of these are considered nutrients of public health concern because low intakes are associated with health problems, which are detailed below (8,10):

CALCIUM

Inadequate calcium intake causes osteopenia, which can lead to osteoporosis and increased risk of bone fractures. Postmenopausal women, amenorrhoeic women, individuals with lactose intolerance, and vegetarians/vegans are at the greatest risk for suboptimal calcium intake.

Potassium

Not eating enough potassium can increase blood pressure, kidney stone risk, bone turnover, urinary calcium excretion, and salt sensitivity. Individuals with inflammatory bowel diseases, those who use diuretics and laxatives, and people with pica are more likely than others to have low potassium intake.

DIETARY FIBER

Only about 5% of the population eats the recommended amount of fiber. Low fiber intake is associated with certain gastrointestinal disorders, such as irritable bowel syndrome, in addition to several chronic illnesses including heart disease, type 2 diabetes, and some cancers.

Vitamin D

Inadequate intake of vitamin D has the potential to lead to osteomalacia and rickets. Breastfed infants, older adults, people with limited sun exposure, people with dark skin, those with inflammatory bowel disease, and those who are obese are at the highest risk of vitamin D deficiencies.

Iron

Low iron intake often leads to anemia, which causes gastrointestinal disturbances and impairs cognitive function, immunity, exercise or work performance, and body temperature regulation. Iron is considered a nutrient of public health concern for young children, pregnant women, and women of child-bearing age.

Other under-consumed nutrients among Americans include choline, magnesium, vitamin A, vitamin E, and vitamin C. Low intakes of these is related to an unhealthy diet in most instances (10). Many multivitamin supplements are developed to address suboptimal intakes of the nutrients listed above. However, it’s generally recommended for most people to obtain their vitamins and minerals from food first (10). Multivitamin supplements may be beneficial when a deficiency of one of these nutrients is present, or when the recommended amounts cannot be obtained from food. If you’re not able to regularly consume foods rich in the nutrients listed above, it’s worth considering taking a multivitamin that contains them to help prevent deficiencies and other health problems.

Water Soluble Vitamins in Multivitamins

Glass of water

Out of the 13 different vitamins, 8 of them are categorized as water soluble. This means they dissolve in water. Among the water-soluble vitamins are vitamin C and B vitamins. Water-soluble vitamins aren’t typically stored in the body, but rather excreted through urine or sweat. For this reason, it’s recommended to consume adequate amounts of them from your diet each day (11). Although the water-soluble vitamins are important for optimal health, it’s not generally recommended to consume greater than the %DV.

Your body simply excretes excess water-soluble vitamins that it’s not able to use or store (11). Some multivitamin supplements contain well over 100% of the DV for water soluble vitamins as a marketing tactic and to increase the price. Under most circumstances, supplementing with excessive amounts of water-soluble vitamins is unnecessary.

Fat Soluble Vitamins in Multivitamins

The fat-soluble vitamins include vitamins A, D, E, and K. These are different from water soluble vitamins in that they dissolve in fat instead of water (11). While your body excretes excess water-soluble vitamins that it’s not able to use, there’s no easy way for it to rid fat-soluble vitamins. Thus, excess amounts of fat-soluble vitamins are known to build up in the body over time, which can damage your tissues and organs. Excessive vitamin A intake may have particularly toxic effects. Multivitamins containing large amounts of vitamin A or beta-carotene have been shown to increase the risk of lung cancer in smokers, and have also been linked to causing birth defects (2).

Although extremely rare, vitamin D toxicity may occur when consumed in excess, which leads to a buildup of calcium in the blood. This can lead to severe complications, such as high blood pressure, kidney failure, and hearing loss (12). Vitamin E and K are relatively nontoxic for most people, but taking megadoses via supplements should still be avoided. Multivitamins formulations typically contain at least one of the fat-soluble vitamins. To avoid overconsumption, it’s best to find one that contains less than 100% of the DV (2). In the case of a deficiency, a higher dose may be recommended by your healthcare provider. However, your blood levels of the vitamin will be closely monitored and the dose will be adjusted accordingly. Most overdoses of fat-soluble vitamins result from taking them in high amounts in supplement form, which is why it’s important to be cautious of what your multivitamin provides (2).

Synthetic vs. Whole Food Multivitamin Supplements

Most multivitamin supplements are made from synthetic vitamins and minerals. This means the nutrients they contain are made artificially in a laboratory setting, which isolates nutrients from sources such as soy, sugar beets, and corn starch. To the contrary, whole food multivitamin supplements are made from concentrated, dehydrated whole foods. These are typically advertised as healthier and easier to absorb than synthetic multivitamins. Additionally, they tend to be more expensive.

It is well-known that our bodies absorb nutrients from whole food sources better than they do from supplements. Whole foods contain a range of vitamins, minerals, antioxidants, fiber, and enzymes that ensure proper digestion, absorption, and metabolism of the food you eat (3). However, to date, there have not been any studies that compare the effects of taking synthetic versus whole food multivitamin supplements. The majority of studies conducted on multivitamins have been performed with synthetic nutrients.

You can determine if the ingredients in your multivitamin supplement are made synthetically or from whole foods by looking at the label. Whole food supplements list food sources in the ingredient list, or are labeled as 100% plant or animal-based. There is not currently enough evidence to recommend whole food multivitamin supplements instead of synthetic. Healthy people are generally recommended to obtain their nutrients from food first before turning to any type of supplement.

Multivitamins for Improved Nutrient Intake

Most multivitamin supplements are made from synthetic vitamins and minerals. This means the nutrients they contain are made artificially in a laboratory setting, which isolates nutrients from sources such as soy, sugar beets, and corn starch. To the contrary, whole food multivitamin supplements are made from concentrated, dehydrated whole foods. These are typically advertised as healthier and easier to absorb than synthetic multivitamins. Additionally, they tend to be more expensive.

It is well-known that our bodies absorb nutrients from whole food sources better than they do from supplements. Whole foods contain a range of vitamins, minerals, antioxidants, fiber, and enzymes that ensure proper digestion, absorption, and metabolism of the food you eat (3). However, to date, there have not been any studies that compare the effects of taking synthetic versus whole food multivitamin supplements. The majority of studies conducted on multivitamins have been performed with synthetic nutrients.

Women’s vs. Men’s Multivitamins

Although women and men need to consume the same vitamins and minerals for optimal health, there are certain nutrients they require in different amounts. For example, the RDA for vitamin C in men is 90 mg/day and 75 mg/day for women. Additionally, men require slightly more vitamin K, choline, magnesium, and zinc than women do (9). On the other hand, women have greater requirements for particular nutrients when they’re at certain life stages. Pre-menopausal women require close to twice the amount of iron than post-menopausal women do.

Further, calcium needs increase in post-menopausal women due to the increased likelihood of bone density loss (2,9). Some multivitamin brands target their formulations towards specific health and wellness interests for each gender. For example, men tend to be more interested in muscle health, while women are often targeted with multivitamins that promote hair, skin and nail health. Despite the heavy marketing of gender-specific multivitamins, there aren’t any studies showing that they provide any particular health benefits besides reduced risk of nutritional deficiencies. The most important consideration for gender-specific multivitamins is to choose one that has a reasonable amount of iron for your gender and age group. This is because the RDA for iron is significantly different between genders as well as life stages for women (2).

Multivitamins for Kids

Approximately one-third of children in the US take multivitamin supplements (15). Parents often encourage their kids to take multivitamins to supplement a poor diet, prevent health problems, and boost immunity. The bottom line is that multivitamin supplements aren’t necessary for most healthy children who are growing normally. While many children are picky eaters, that doesn’t necessarily mean that they have nutritional deficiencies. Some children with the following nutritional risks may benefit from multivitamin supplementation (2)

Anorexia or poor appetite
Presence of chronic disease
Come from deprived families or suffer parental neglect or abuse
Participate in dietary programs for managing obesity or follow fad diets
Consume a vegetarian or vegan diet without adequate dairy products

When choosing multivitamins for kids, it’s important to find one that provides less than 100 percent of the DV for vitamins and minerals. Children are more susceptible to complications from megadoses due to their smaller size (15). Multivitamins formulated for kids often have a focus on nutrients that promote normal growth and development, such as vitamin A, B vitamins, calcium, and iron. Additionally, many multivitamins targeted towards kids are full of added sugars and lead children to believe that they’re candy. For this reason, it’s important to keep them out of their reach to prevent overdoses.

Multivitamins for Beauty

Some multivitamin brands formulate products specifically for their potential to promote beauty through improving hair, skin, and nail health. With the exception of biotin supplements, products like these have never been proven to have their claimed benefits. However, they’re certainly worth a try if you have specific beauty goals (16). Listed below are common vitamins and minerals added to beauty-based multivitamins (8,16):

Omega-3 Fatty Acids

Help reduce inflammation; can also prevent dryness by adding lubrication and moisture to hair, skin, and nails.

Vitamin A

Known for its potential to help treat acne; adequate intake may prevent blockages of dead skin cells in hair follicles.

Vitamin E

Has antioxidative properties that help protect your skin from sun damage, which may prevent the formation of dark spots and wrinkles.

Vitamin C

Functions as an antioxidant in the body and plays an important role in collagen production. Known for its potential to prevent skin cell damage, heal wounds, and reduce the appearance of wrinkles. Helps maintain strength and integrity of hair and nails.

Vitamin E

Helps maintain a healthy heart; protects cells from inflammation.

Zinc

Supports the growth and division of cells, which is necessary for proper growth of hair and nails.

Biotin

Plays a role in maintaining normal cell growth, which promotes growth and strength of hair and nails.

B Vitamins

Contribute to the development of red blood cells and iron absorption, which are necessary to maintain the growth and pigment of healthy nails.

Iron

Carries oxygen to your cells, which is essential for keeping your skin, hair, and nails strong and healthy.

PROTEINS

Boosts keratin production, which helps keep your hair and nails strong.

Magnesium

Involved in protein synthesis, which supports the growth of hair and nails.

Prenatal Multivitamins

Prenatal Multivitamins

Prenatal multivitamins are specially formulated to meet the increased demand for vitamins and minerals during pregnancy (2). While prenatal multivitamins shouldn’t replace eating healthy foods, they can help address nutritional gaps that child-bearing women may have in their diet. They’re meant to support the overall health of the mother and the growing baby.

Many studies have shown that taking multivitamins that provide folic acid before and during pregnancy may help prevent complications, such as pre-eclampsia and neural tube defects (17,18,19). For example, one study found folic acid supplements to reduce the risk of neural tube defects in pregnant women by 72% (20).

Taking prenatal multivitamins is especially important for pregnant women who struggle with problems such as nutrient deficiencies and hyperemesis gravidarum. Additionally, those who restrict certain food groups due to allergies or following a specific diet may need to take a prenatal multivitamin (2,21). Prenatal vitamins contain more of a few specific nutrients compared to standard multivitamins, which are listed below (8):

Folic Acids

Taking sufficient amounts of folic acid in the first month of pregnancy reduces the risk of neural tube defects in newborns. Women of childbearing age who might become pregnant are recommended to obtain 400 mcg/day of synthetic folic acid, and the recommendation increases to 600 mcg/day for pregnant women.

Iron

Essential for the baby’s growth and development; also prevents iron deficiency anemia. The DRI for iron in pregnant women is 27 mg/day.

In addition, prenatal vitamins often provide extra calcium, vitamin D, magnesium, and omega-3 fatty acids. It’s important for pregnant women to speak with their doctor before taking a prenatal vitamin. They’ll be able to recommend a specific formulation based on health history, nutritional needs, lab values, and medications. As with other populations, pregnant women should avoid prenatal multivitamins that contain megadoses of nutrients. Too much of certain nutrients, especially fat-soluble vitamins, can have toxic effects on the body and lead to birth defects (2). For example, taking excess vitamin A during pregnancy can increase the risk of birth defects in infants (2).

Multivitamins for Breastfeeding

Breastfeeding women are commonly recommended to take a multivitamin supplement to ensure they get the nutrients they need for postnatal health. Many women opt to continue taking their prenatal multivitamins after giving birth. This is generally safe, although prenatal multivitamins typically contain more iron than what the mother needs after the baby is born. A daily multivitamin that contains 100 percent or less of the RDAs is another option that will help support the nutritional needs of breastfeeding moms.

Multivitamins that provide vitamin D may be beneficial for women who breastfeed as well, especially if a deficiency is present. Vitamin D is required to support healthy bone development and prevent rickets in infants (2). Although infants are typically supplemented with vitamin D, some of their needs are met through breastmilk so it’s important that their mother’s vitamin D levels are sufficient (2). There are several postnatal multivitamins on the market that are advertised to breastfeeding moms. These typically contain a combination of vitamins, minerals, and omega-3 fatty acids. Multivitamins formulated specifically for breastfeeding likely won’t cause any harm, but there isn’t any scientific evidence to support their use over prenatals or regular multivitamins.

Multivitamins that Contain Fiber

Some multivitamins have fiber added to them to support digestive health. It’s typically in the form of prebiotic fiber, such as inulin, which helps balance healthy gut bacteria and boosts the immune system. Multivitamins that contain fiber are helpful if you don’t include a lot of fiber-rich foods in your diet, such as fruits, vegetables, legumes, nuts, seeds and legumes. However, it’s generally recommended to obtain fiber from food first. If you start taking a multivitamin that contains fiber, it’s beneficial to increase your water intake at the same time to help prevent unpleasant side effects, such as bloating and constipation. Additionally, a rule of thumb is to find a multivitamin that doesn’t include an excessive amount fiber. In general, 3-5 grams of fiber per serving is sufficient for most people.

Multivitamins that Contain Probiotics

Some multivitamins on the market have probiotics added to them. Probiotics are good bacteria that reside in your intestines to promote digestive health and immunity. Many people take probiotics separately from their multivitamin supplements. Including them in multivitamin formulations adds convenience and may help your body use the vitamins and minerals more efficiently. This is because probiotics help aid nutrient absorption in the gut.

A few studies have shown combining probiotics with multivitamins to be helpful for immune system support (22, 23). In one study, adults who took a multivitamin containing probiotics had a 14% lower risk of developing respiratory tract infections and reduced the severity of symptoms in common colds than those who didn’t take the supplement (22). Probiotic supplements may also be used to help treat and prevent diarrhea, irritable bowel syndrome, inflammatory bowel disease, urinary tract infections, H. pylori, and eczema in children (23). With that being said, more research is needed in order to understand the impact of taking multivitamins combined with probiotics.

There are many different strains of probiotics and their effectiveness varies person-to-person. If you choose to take a probiotic-containing multivitamin, you may need to try a variety of brands and strains before you find one that works for you and the symptom you’re trying to address

Multivitamins for Nutritional Deficiencies

There are several instances that could make you more susceptible to nutritional deficiencies, including the following (1):

Excessive Losses

Hemodialysis, excessive vomiting or diarrhea, menstruation

Abnormal Metabolism

Genetic polymorphisms, alcoholism, conditions that impair absorption

Inadequate Synthesis

Insufficient sunlight exposure

If you have or are at risk of a nutritional deficit, you may be recommended to take a multivitamin. Your doctor will provide you with the exact dosage you need if you have a confirmed nutrition deficiency. Since multivitamin formulations vary widely, it’s important to select one that focuses on your nutrient of concern. If you’re deficient in only one nutrient, it’s worth considering taking a supplement for that nutrient only, rather than a multivitamin that combines multiple different nutrients.

Multivitamins for Boosting the Immune System

There are not any specific studies that show taking multivitamins is helpful for promoting immunity. However, the nutrients they contain may help support a healthy immune system. Vitamin C, for example, is typically added to multivitamins formulated for immune system support. Consuming adequate vitamin C has been shown to reduce the severity and recovery time for common colds (24). Here is a list of other vitamins and minerals that are commonly added to immune-boosting multivitamin supplements:

Vitamin a Vitamin d Vitamin e Vitamin b6 Vitamin b12 Folid acid Biotin Pantothenic Acid Zinc Selenium

All of these nutrients have unique antioxidative properties that are known to benefit the immune system and reduce the risk of certain illnesses (8). Taking multivitamins for immunity support is certainly worth a try, especially if your diet is low in fruits and vegetables. Additionally, if you have a compromised immune system, taking a multivitamin that contains immune-boosting vitamins and minerals may prove to benefit your health.

Multivitamins for Older Adults

Our bodies have different needs as we get older and certain nutrients become especially important for optimal health. Multivitamins for older adults are formulated to address vitamins and minerals that their diets tend to fall short in. Listed below are nutrients focused on in most multivitamins for seniors (2,8).

Calcium and Vitamin D

Older adults are prone to bone disorders, such as osteoporosis, as well as fractures. For this reason, their calcium and vitamin D needs are higher compared to younger adults.

Vitamin B12

People over age 50 may be less able to absorb the protein-bound, naturally occurring vitamin B12 in food. Supplementation is often recommended to prevent a deficiency, which can cause difficulty walking, forgetfulness, changes in personality, weakness, and anemia in older adults.

Potassium

Added to multivitamins to support heart health in older adults.

Fiber

Often provided by multivitamins for older adults, as many don’t meet their recommended needs for fiber. Fiber is important for preventing constipation and reducing risk of heart disease and type 2 diabetes.

It’s worth mentioning that most older adults don’t need a complete multivitamin supplement. Making diet changes alone can help improve their overall nutrient intake and prevent the need for a multivitamin. Multivitamin supplements are typically recommended for older adults if a deficiency is present or their diet doesn’t provide adequate vitamins and minerals (2).

Multivitamins for Weight Loss

There is not currently any scientific evidence to support the use of multivitamins for weight loss. Many multivitamin brands claim that their formulations help increase metabolism or burn fat, without any research to back up these statements. Additionally, there is nothing multivitamins will do to promote weight loss that a healthy diet and exercise won’t do. While adding a multivitamin to your regimen will increase nutrient intake and correct existing deficiencies, it won’t substitute for other lifestyle changes required to obtain a healthy weight. Listed below are a few vitamins, minerals, and other ingredients you may find in multivitamins developed to promote weight loss:

Vitamin B12
Vitamin d
Omega-3 Fatty Acids
calcium
Green Tea Extract
magnesium

All of these nutrients and ingredients are claimed to help with weight loss due to their ability to improve metabolism. However, the best way to consume more metabolism-boosting vitamins and minerals is by eating a balanced diet that includes a variety of nutritious foods (8,10).

Multivitamins for Athletes

Many athletes take multivitamins to improve energy levels and help boost performance in workouts and sporting events. Although some studies show that extreme athletes have increased needs for certain nutrients, there’s not enough research to conclude exact recommendations for multivitamins in athletes. Regardless, there are a variety of vitamins and minerals that can certainly support the health of athletes. A list of common nutrients found in multivitamins for athletes is listed below (8):

B Vitamins

Required for energy production and metabolism. Help break down carbohydrates and amino acids in the body.

Irons

Helps transport oxygen through the body, which is important for preventing fatigue and maintaining optimal performance in athletes.

Vitamin A

Functions as an antioxidant in the body, may help lower inflammation which can help with soreness and promote recovery.

Vitamin D & Calcium

Supports bone health, keeping them strong; also required for nerve function and hormone release.

Some multivitamins formulated for athletes contain extra ingredients, such as amino acids, caffeine, and tart cherry extract. Taking multivitamins has the potential to improve athletic performance. However, it’s generally recommended for athletes to obtain the majority of their vitamins and minerals from a nutrient-rich diet before relying on supplements.

Multivitamins for Vegetarians and Vegans

Through careful planning, it is possible to meet your nutritional needs on a vegetarian and vegan diet. However, certain nutrient requirements are more difficult to meet through diet alone with the avoidance of animal products, which may warrant the need for a multivitamin. Listed below are several nutrients you may need to supplement with a multivitamin if you follow a vegetarian or vegan diet (1).

Vitamin B12
Vitamin d
Iodine
Omega-3 Fatty Acids
calcium
Zinc
Iron

There aren’t many multivitamins on the market specifically formulated for vegetarians and vegans. However, multivitamin supplements that provide the nutrients listed above are fairly easy to find. It’s important to note that some multivitamin supplements contain animal-based additives, such as gelatin, that aren’t typically consumed by vegetarians and vegans. If you follow one of these diets, it will be important to double-check ingredient labels before purchasing a multivitamin.

Multivitamins for Diseases and Conditions

Many multivitamins are advertised for their potential to help with specific diseases and conditions. Although they can support certain health goals, taking multivitamins has never been proven to prevent, treat, or cure any health conditions. Most studies that have researched the role of multivitamins in enhancing health and preventing disease have been observational. This type of research can suggest an association, but does not prove a causal relationship (1,2). Additionally, studies conducted on multivitamins are difficult to compare. Participants in these studies use various multivitamin formulations that include different mixes and doses of nutrients (1,2). The relationship between taking multivitamins and disease prevention has been studied most extensively for heart disease, cancer, brain function and eye health which are detailed below.

Multivitamins and Heart Disease

Some people take multivitamins to improve their heart health. However, the evidence that multivitamins can lower the risk of heart disease is mixed. Most studies have found no association between the use of multivitamins and heart disease. Individuals taking multivitamins do not appear to have fewer heart attacks, strokes, or heart-related deaths (2). More research is needed before a formal conclusion can be made about the role that taking multivitamins has in heart health. It’s also worth mentioning that multivitamins can’t improve heart health if other risk factors aren’t controlled, such as poor diet and smoking. With that being said, taking a multivitamin to support heart health in combination with a healthy diet and lifestyle is unlikely to cause any harm. Some multivitamins are formulated with specific nutrients and ingredients to support heart health, such as those listed below (8):

Omega-3 Fatty Acids

Help reduce inflammation.

Vitamin D

May help regulate blood pressure, which is a major risk factor for heart disease.

Magnesium

Helps maintain the heart's electrical properties.

CoQ10

An antioxidant that may improve heart function by reducing oxidative damage.

Folic Acid

Helps break down an amino acid in the blood called homocysteine, which is related to higher risk of heart disease when elevated.

Potassium

Keeps blood pressure under control, especially in combination with a low-sodium diet.

Multivitamins for Brain Function

Multivitamins have never been proven to enhance brain function, but some studies have linked taking them with improved memory and mood in certain populations. For example, several randomized controlled trials have found multivitamin supplementation to enhance memory retrieval in older adults. They’ve also been shown to help reduce symptoms of depression and improve feelings of general day-to-day wellbeing (28,29,30). In one study, older adults who took a multivitamin supplement for 16 weeks were found to have improvements in their brain activity and were able to recall memories more quickly than those who didn’t take multivitamins (31). There are many multivitamin brands with formulations that claim to improve brain health, including the following nutrients (8):

Omega-3 Fatty Acids

Help reduce inflammation in the brain, which has the potential to delay onset of Alzheimer's disease and prevent other brain disorders.

Vitamin D

May protect the brain against cognitive decline and dementia.

B Vitamins

Folid acid, vitamin b6 and vitamin b12 help reduce blood levels of homocysteine, which may increase risk of Alzheimer's disease when levels are too high.

Nutritional deficiencies are linked with several mood disorders, such as depression, so it makes sense that some people report improved brain health after taking multivitamins (32).

Multivitamins for Eye Health

There is some evidence that taking multivitamin supplements may be beneficial for eye health. For example, multivitamins that provide antioxidative vitamins and minerals may help slow the progression of age-related macular degeneration, which is a leading cause of blindness. Additionally, taking multivitamins has the potential to reduce the risk of common eye diseases, such as cataracts (33,34). Multivitamins developed to promote eye health may contain the following vitamins and minerals (8).

Vitamin A

Helps maintain the strength and clarity of your cornea, the outside covering of your eye. Also a component of rhodopsin, a protein in your eyes that makes it easier for you to see in dim light.

Vitamin E

Has antioxidative properties that protect your eye cells from damaging free radicals.

Vitamin C

Has antioxidative properties, similar to vitamin E. Also required to make collagen, a protein that provides structure to your eyes.

Lutein and Zeaxanthin

Antioxidants that help protext your eyes from blue wavelenghts, which can be harmful.

B Vitamins

Help lower levels of homocysteine, which is associated with inflammation when elevated and may also increase risk of developing age-related macular degeneration.

Absorbtion of Multivitamins

The first step to making sure you absorb the nutrients from your multivitamin properly is to follow the instructions the manufacturer provides. It may be recommended to take it with or without food, or at a specific time of day, to improve absorption (3). Additionally, it’s important to keep in mind any other supplements or medications you’re taking that may compete with absorption of the multivitamin. For example, if you take a large dose of a mineral, such as calcium or magnesium, it will compete with other minerals to reduce their absorption.

Thus, calcium and magnesium supplements should be taken separately from multivitamin supplement (35). Some nutrients have the ability to enhance absorption of other nutrients. Vitamin C, for example, can increase iron absorption from supplements. Fat soluble vitamins A, D, E, and K are better absorbed if taken with a fat-containing meal (8,35). Absorption issues aren’t a major concern when taking a multivitamin that stays within the DRIs of vitamins and minerals. Unless the multivitamin contains more than 250 mg of either calcium or magnesium, absorption is unlikely to be impaired (35).

Risk of taking multivitamins

Multivitamins are generally safe for most people to take. However, there are some risks to be aware of before taking them, including the following (1,2).

Toxicity

Occurs when you take excessive amounts of a vitamin or mineral. This is mostly a concern for vitamins that build up in your body, including Vitamin A, D, E, and K. To prevent toxicities, you should avoid taking multivitamins that contain more than the Tolerable Upper INtake Level (UL) for vitamins and minerals and follow the recommended dosage.

Medication Interactions

Multivitamins may interact with certain medications, such as warfarin. Talk to your healthcare provider to determine if multivitamins are safe to take with your medications.

Iron Overload

Adult men and postmenopausal women should avoid taking multivitamins that contain 18 mg or more of iron unless recommended by their doctor. Iron supplements are also a leading cause of poisoning in children under age 6. Any product containing iron should be kept out of children’s reach.

Increased Risk of Disease

Multivitamins that provide large amounts of vitamin A or beta-carotene may increase risk of lung cancer in smokers and former smokers. Birth defects: Taking excessive vitamin A during pregnancy can increase risk of birth defects in infants.

Most risks associated with taking multivitamins are related to excessive intake of certain nutrients. Individuals who take multivitamins in addition to single vitamin and mineral supplements tend to be at greater risk for excessive intake or toxicities (1,2). Additionally, those who consume a nutrient-dense diet or fortified foods on a regular basis, in addition to taking multivitamin supplements, may be more likely to experience a toxicity or adverse reaction.

Multivitamin Side Effects and Allergic Reactions

There are a few side effects you may experience when taking multivitamins, which are listed below (36):

Constipation
Diarrhea
Upset Stomach

It’s important to double-check the label of multivitamins before taking them to learn of any potential side effects. These may vary from manufacturer to manufacturer, depending on the formulation. Side effects of multivitamins are typically short-lived and likely to subside as your body adjusts to them. You may experience different side effects depending on your stage of life and if you have certain health conditions (35).

Taking certain multivitamin supplements with food may help reduce gastrointestinal side effects. For example, taking magnesium with food can prevent diarrhea, and taking iron with food can reduce the chance of stomach upset (35). Allergic reactions to multivitamins are rare. You should seek immediate medical attention if you notice any of the following symptoms of a serious allergic reaction after taking your multivitamin: rash, itching/swelling, severe dizziness, and trouble breathing.

Multivitamin Interactions with Medications

Supplement pills in a wooden spoon

Multivitamins that provide nutrients at or below recommended intake levels do not generally interact with medications. With that being said, if you take any medications, you should always speak with your doctor before adding a multivitamin supplement to your regimen. If you take medications to reduce blood clotting, such as warfarin, you may need to avoid multivitamins that contain vitamin K before speaking with your healthcare provider (2).

Vitamin K is involved in blood clotting and decreases the effectiveness of warfarin and similar drugs. Your medication dosage depends partly on the amount of vitamin K you consume on a regular basis. If you want to take a supplement that provides vitamin K, your doctor can help change the dosage of your medication or recommend a different multivitamin (2). Additionally, you should avoid taking more than one multivitamin product at the same time, unless recommended by your doctor. Taking several multivitamin products together can result in a vitamin toxicity or other serious side effects.

Should You Take a Multivitamin?

There are many reasons why you might consider taking a multivitamin. It is extremely important to consult with a healthcare provider when deciding whether to take a multivitamin. They’ll be able to provide you with an individualized recommendation, based on your health history, stage of life, gender, age, and goals. Although there isn’t adequate research to support the use of multivitamins for disease prevention, there are a few populations susceptible to nutrient deficiencies and/or complications related to inadequate nutrient intake. The following populations are typically recommended to take a multivitamin supplement (1,2):

Woman of child bearing age

Recommended to obtain adequate folic acid to prevent neural rube defects in newborns during the first month of pregnancy. Prenatal multivitamins are often suggested to meet folic acid needs.

Pregnant women

Prenatal multivitamins that provide folid acid and iron are recommended.

Postmenopausal women

May need to take multivitamins that provide calcium and vitamin D to support bone health.

Older Adults

May benefit from taking a multivitamin that contains vitamin B12, due to decreased absorption of the vitamin through the aging process.

Children at nutritional risk

Those with various risk factors such as chronic disease or failure to thrive may benefit from taking multivitamin supplements.

Restricted diets

Those who eliminate entire food groups from their diets, such as vegans, may require a multivitamin supplement.

Conditions that deplete nutrients

People with diseases or conditions that impair absorption and digestion of nutrients, such as cancer and chronic gastrointestinal problems, may be recommended a multivitamin supplement.

Nutrient deficiencies

Those diagnosed with a true nutrient deficiency may be recommended to take a multivitamin or supplement that provides a single vitamin or mineral.

Nutrient-poor diets

Those who are unable to eat a balanced and varied diet may benefit from taking a multivitamin.

For the rest of the population, deciding whether to take a multivitamin is a personal choice. However, multivitamins should never take the place of eating whole, real foods (10). If you struggle to make healthy food choices, it may be beneficial to speak with a professional, such as a registered dietitian, who can help you improve your diet. No US government health agency, private health group, or health professional organization promotes regular use of multivitamins without first considering overall diet quality. While multivitamins can certainly help you improve your nutrient intake, they should not be used as a bandaid for an otherwise unhealthy diet and lifestyle.

Tips for Choosing the Right Multivitamin Brand

Choosing the right multivitamin brand can be incredibly overwhelming given the hundreds of different products on the market and the significant claims behind them. It’s important to do your research before selecting a multivitamin supplement, due to the minimal amount of regulation they require. Many multivitamin supplement manufacturers provide in-depth information about their products and development process online. You can also contact manufacturers directly via phone or email to have your questions and concerns addressed.

Questions to Ask Multivitamin Manufacturers

Listed below are a few questions you may consider asking manufacturers before purchasing their multivitamin supplements:

If claims are made about the multivitamin, such as weight loss support, what information do they have to back these up? Evidence from high-quality scientific research, such as randomized controlled trials, is the gold standard. Anecdotes from consumers is not considered scientific evidence.

Has the manufacturer gone through any testing to verify the safety and/or effectiveness of their product?

Do they follow good manufacturing practices and third-party verification to determine if the multivitamin contains what’s stated on the label and isn’t contaminated with toxic ingredients?

Does the company have any reports from consumer or healthcare professionals about adverse effects from using their products?

Having reliable answers to these questions will allow you make an informed choice about what multivitamin to take. Another important consideration is to talk to your health care provider before choosing a multivitamin supplement. They’ll be able to make an individualized recommendation based on your health history, nutritional needs, genetics, lab values, medications and more.

Look For the Right Balance of Nutrients

The formulation of the multivitamin you choose should be well-balanced. Your multivitamin should help fill gaps for nutrients your diet falls short in, without providing excessive amounts that can cause harm. This is important for preventing toxicities and adverse reactions. Additionally, it will ensure you’re not paying extra for excessive nutrients that are just excreted by your body.

Price Isn’t Everything

Some people are tricked to believe that the higher the price of a product, the higher quality it is. This isn’t necessarily the case when it comes to multivitamins. “Less is more” in the case of multivitamins. They should contain vitamins and minerals, and may contain a few extra ingredients as fillers or stabilizers, such as cellulose or gelatin. Excessive amounts of extra ingredients and additives will just drive up the price.

Watch Out for Claims

Excessive, unrealistic claims made by multivitamin brands are typically too good to be true. Never choose a multivitamin brand based on the claims the company makes. Do your research, ask the right questions, and make an informed choice based on your own knowledge, instead of what the company tries to tell you.

The Bottom Line – Are Multivitamins Worth It?

Multivitamins are incredibly popular, over one-third of Americans take a multivitamin. People take multivitamins for a variety of reasons: to increase nutrient intake, promote health, treat nutritional deficiencies, and reduce the risk of disease. Specific populations such as pregnant women, older adults, individuals with a poor or restricted diet, and individuals who avoid certain foods (such as vegetarians, and vegans) may be recommended to take a multivitamin. It’s important to note that multivitamins are never intended to cure disease (1,2). However, healthcare providers may recommend multivitamins to patients with specific medical conditions.

Additionally, you should always talk to your health care provider before taking a multivitamin. They’ll be able to make specific recommendations depending on your age, gender, medications, and health conditions. A multivitamin should never replace a healthy diet. Multivitamins are beneficial to people who do not get enough vitamins from food alone. Instructions for dosage and timing of taking multivitamins should always be followed appropriately (1,2). Multivitamins are generally safe for most people and are certainly worth a try if you want to boost your nutrient intake.